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Sky Hunting with Small Refractors - March, 2011


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#1 MistrBadgr

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Posted 26 February 2011 - 02:52 PM

Sky Hunting with Small Refractors – March, 2011

Here is the list for March.  It includes eight double stars from the Astronomy League’s List, only one nebula, but ten open clusters, some of which have different designations than we have had before.  This month, we will definitely become familiar with the Unicorn!

We will be exploring in the constellations Aurigae, Gemini, Monoceros, Canis Major, Lyncis and Puppis. 

March Double Stars:

Item                                            R.A.                Dec.            Mag.         Sep.       P.A
 

Theta Aurigae                       05h 59.7m         +37d 13’      2.6, 7.1            3.6”        313d

Epsilon Monocerotis             06h 23.8m         +04d 36’      4.5, 6.5        13.4”      27d

Beta Monocerotis                06h 28.8m          -07d 02’        4.7, 5.2          7.3”     132d

12 Lyncis                               06h 46.2m      +59d 27’       5.4, 7.3          8.7”    308d

Epsilon Canis Major              06h 58.6m        -28d 58’    1.5, 7.4          7.5”    161d

Delta Geminorium              07h 20.1m      +21d 59’    3.5, 8.2          6.8”      211d

19 Lyncis                            07h 22.9m        +55d 17’    5.6, 6.5          14.8”    315d                                                                                 

Alpha Geminorum              07h 34.6m      -31d 53’      1.9, 2.9           2.2”    171d

Open Clusters:
                                                   R.A                   Dec.             Mag.        Size        Const.

Messier 35 (NGC 2168)         06h 08.9’         +24d 20’           5.1        28’        Gemini

Collinder 89                        06h 18’        +23d 38’    5.7         35’       Gemini

Collinder 106                      06h 37.1’      +05d 57’        4.6            45’    Monoceros

Collinder 107                      06d 37.7’         +04d 44’         5.1            35’        Monoceros

NGC 2264 (Christmas Tree)  06d 41.1'          +09d 53'          3.9            20'        Monoceros

Messier 50 (NGC 2323)        07d 03.2'          -08d 20'            5.9          16'        Monoceros

Messier 41 (NGC 2287)        06d 47.0'          -20d 44'            4.5          38'        Canis Major

Messier 47 (NGC 2422)        07d 36.6'          -14d 30'            4.4            29'        Puppis

Messier 46  (NGC 2437)        07d 41.8'          -14d 49'            6.1            27'        Puppis

Messier 93  (NGC 2447)        07d 44.6'          -23d 52'            6.2            22'        Puppis

Nebula:

Rosette Nebula (NGC 2237)  06d 32.2'          +05d 03'                        80' x 60'    Monoceros

I will post continuations for how to find them.

Thanks,

Bill Steen

#2 Philip Pugh

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Posted 27 February 2011 - 05:03 AM

Alpha Geminorum (aka Castor) is a tough one to split but I've got a few pics on my website.

M35 is pure eye candy through a medium sized telescope.

If you're up late, check out the Beehive (M44). I've managed to take some decent snaps of it using a compact digital camera. Again, check my website.

#3 MistrBadgr

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Posted 27 February 2011 - 02:17 PM

Thanks, Philip!

#4 MistrBadgr

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Posted 03 March 2011 - 04:41 PM

Sky Hunting with Small Refractors – March, 2011 (continuation 1)

This is a bit long, with all eight double stars discussed, but I thought it would be better to get this posted for you to use before I get busy with work.

March Double Stars:

Item                                            R.A.                Dec.            Mag.         Sep.       P.A

Theta Aurigae                       05h 59.7m         +37d 13’      2.6, 7.1            3.6”        313d

In order to find this star, we first need to talk about some sign-posts now in the sky.  From my yard at 36 degrees North Latitude, Orion is in the sky to the South and west.  You can recognize it by the three stars in his belt that are somewhat horizontal, then his sword that hangs straight “down” or North and South. From the western star in Orion's belt, Mintaka or Delta Orionis, we jump straight North 28 degrees to Gamma Auriga or Elnath.  This is a little less than three fist widths at arms length.

Elnath is the Southern-most major star in the main figure of Auriga.  Northeast of Elnath (maybe a
little more North than east ) roughly ten degrees, or a about a fist width, is Theta Auriga.

The Night Sky Observer's guide says the A star is white and B is bluish.  In our small scopes, the B star will most likely look a shade of gray.  Since a blue color is normally associated with very large hot stars and the primary is white, I am not sure how the smaller star can really be blue.  With the fairly large difference in magnitudes and a separation of 3.6, it will take the 9mm eyepiece that comes with an NG-70 to make the split.

Epsilon Monocerotis             06h 23.8m         +04d 36’      4.5, 6.5        13.4”      27d

Monocerotis, the Unicorn, is located just east of the upper body of Orion.  Epsilon also has the number 8 assigned to it, making it the 8th most westward star in the constellation, of those assigned such a designation.  It is the point of the Unicorn’s horn as it is drawn in The Night Sky Observer’s Guide and not all that far from Betelgeuse, the eastern shoulder star of Orion.  If you draw a line from Lambda Orionis, sort of the “Head” star of Orion through Betelgeus, and on about one and a half times that far to the east, Epsilon Monocerotis will be just a little bit North of that point.  With a separation of 13.4” the two stars will show roughly the same width as the long diagonal across the trapezium or a little more.  At Magnitudes of 4.5 and 6.5, the two stars show up easily in a 60mm scope with light pollution.  B is Southwest of A.  Both are yellow white stars.

Beta Monocerotis                06h 28.8m          -07d 02’        4.7, 5.2          7.3”     132d

In the stick figure shown in The Night Sky Observer’s Guide, Beta is the lowest point in the foreleg.  If you draw a line eastward from Rigel through kappa Orionis and on eastward in a straight line, and then extent Orion’s belt eastward, the two will intersect at a point South of Beta a little ways.  Beta is the bright star near that intersection point.  Even though the Astronomy League only mentions A and B in their list, this is a very pretty triplet of almost equal stars with another dimmer one farther away.  The Night Sky Observer’s Guide the Magnitudes in order are 4.7, 5.2, 6.1, and 12.2.  The seperations are as follows:  AB- 7.3, AC- 10.0, AD- 25.9, BC- 2.8.  I was able to split B and C with the 70mm refractor and believe I could have with the 60mm.  I could not identify the D star.  I was pleasantly surprised to see three stars when I was expecting two and doubted that I had the right object until I checked it out in a better reference than the observing list I was using.

12 Lyncis                               06h 46.2m      +59d 27’       5.4, 7.3          8.7”    308d

The Lynx constellation is a bit of an enigma for me.  There are no really bright stars in most of it.  It is fairly long and stretches in a Northwestern to Southeastern general direction.  It is Northwest of Gemini and Auriga, and Southeast of Ursa Major.  Camelopardalis is on its North and Cancer on its Southern end.  It is sort of a big hole between the others in my paradigm.  There will be one star, in the Southeastern part of the constellation that is easy to find in the April list.  The two in this month’s batch are not what I would call beginner friendly. 

Last year, I could not find this one, but I did find it this year!  The trick for me is to look for it when it is near zenith.  From my back yard, it is nearly overhead.  This makes it somewhat difficult to sit low enough to get to the eyepiece, but there is much less air and dust particles in the way.

The reference stars for finding it this year were in Auriga.  We found Theta Auriga earlier. Northwest of Theta about a fist width is a very bright star Capella, or Alpha Auriga.  To the east of Capella is a star about as bright as Theta about five degrees or a half of a fist away.  This is Beta.  About eight degrees or three quarters of a fist width straight North of Beta is Delta.  Delta is not as bright as I think it should be, considering the brightness of Theta and some other, but it is brighter than any of the other stars around it.  For me, with my light pollution, it is really pretty dim and I have to look for it.  Cappella and Delta Auriga are the reference stars we need.

Go from Capella to Delta and then travel on about three-fourths of the distance from Capella to Delta. You will be almost on top of 12 Lyncis.  If you look at a star map with lines drawn for the major stars, you will see the two NW end stars have the numbers 2 on the end with 15 being the next one.  When you look through your scope, there will be a whole bunch of stars around 2 that make it a little difficult to distinguish it.  However, 15 stands out fairly well.  Near 15, on the same side as 2 will be two stars just to the North of a 15 to 2 line.  Those two stars line up themselves to point at 2, even though they are close to 15.  These two stars are 14 and 12.  12 is the one farthest away from 15.

There are many double stars in the area.  In order to make sure you have the right one, you need to see the orientation of the two stars compared to west.  Just watch the stars for a moment and let them move across your field.  They will travel toward the west.  The line from A to B will be clockwise from west about 45 degrees.  With a two magnitude difference, A definitely looks brighter than B.  I was able to just barely detect that the star was double by the way it twinkled with a 26mm eyepiece.  To actually see the split takes maybe a 15 mm eyepiece or shorter.

Epsilon Canis Major              06h 58.6m        -28d 58’    1.5, 7.4          7.5”    161d

This one was pretty easy to find.  Look for Sirius.  You can’t miss it.  The very bright star to the east and slightly South of Orion.  The big dog is sitting on his haunches facing Orion.  Beta, is a bright star to the right of Sirius which I think if as the dog’s nose.  The dog’s back angles downward and to the left of Sirius to Delta.  Then, follow the line of the dog’s haunch to the right and down from Delta to Sigma, and then a little crook to Epsilon.  Epsilon is not quite as bright as Delta.  The two stars in Epsilon have magnitudes of 1.4 and 7.5.  B can be seen.  But it is very dim in the glare of A.

Delta Geminorium              07h 20.1m      +21d 59’    3.5, 8.2          6.8”      211d

Looking at Gemini, the twins, it is easy to spot Castor and Pollux.  I am not sure why Castor is Alpha and Pollux is Beta.  Pollux is definitely brighter than Castor.  In March, in the early evening, they are fairly well overhead from my back yard in Northeastern Oklahoma.  Pollux, the brightest of the twins, is the one to the South.  As you travel down that left column of Gemini, Delta is the next major star you come to.  On some star maps, it may be shown as 55 Gemini.  I could not split this one with my 70mm scope.  It may have been weather conditions as well as light pollution.  There are also some other contributing factors.  The Astronomy League list states that the two stars are 6.8” apart.  Referring to The Night Sky Observer’s Guide, it states that they are 5.8” and closing.  Additionally, the nearly five magnitude difference expands the limit for a 70mm refractor to around 5 arc seconds under the best condition, which these were not.  This is one of the challenges of the Astronomy League’s list.  It is easy to find.  But, is hard to split…..and getting worse.

19 Lyncis                            07h 22.9m        +55d 17’    5.6, 6.5          14.8”    315d                                                                                 

This is the other tough one for me in Lyncis.  I really do not know why it has been that tough.  I did find it this year, with the Lynx nearly overhead.  As we discussed with Lyncis 12, we used the stars Alpha Auriga (Capella) and Delta Auriga to point to the area of 2 Lyncis and 15 in order to find 12.  If you follow the line from 2 to 15, at 15 make a 30 degree turn toward the South and go the same distance as between 2 and 15.  You should be on top of 19.  I could not actually see any of these stars from my back yard with my eyes.  I could, however, see them with a pair of binoculars.  The challenge for me was translating what I could see in the binoculars to a position in my finder scope.  After several attempts, I did.  19 is a pair of stars that look pretty equal.  They are farther apart than 12 and I could see the split with a 25mm eyepiece in my NG-70.  Since the Lynx is riddled with double stars, make sure you watch for movement to the west and verify the Primary Angle, it should be 45 degrees North of west.

Alpha Geminorum              07h 34.6m      -31d 53’      1.9, 2.9           2.2”    171d

Gemini is Northeast of Orion, with Castor and Pollux, the heads of the twins three and a half or four fist widths away.  Castor, Alpha Geminorum, is at the top, is the dimmer of the two brightest stars, and is the Northeastern one of the two.  There are actually three stars to be seen with amateur telescopes.  The ones I saw with my 70mm were A and B, which I was able to split.  I could not identify C, which is located 72.5 away from A with a PA of 162 degrees (SSE) at a magnitude of 8.8.  With most scopes small or middle size, there will not be enough light gathering ability to activate the cones in our eyes.  But, C is listed as being Lilac in color.  I would like to see this in a big scope.  I have never heard of a lilac star before.  This is another case of easy to spot and hard to split for a little bit different reasons than delta.  The magnitudes are fairly close.  The separation is small.

Hop your skies are clearer than mine are tonight!

Bill Steen

#5 MistrBadgr

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Posted 05 March 2011 - 09:14 PM

Sky Hunting with Small Refractors – March, 2011 (continuation 2)

Open Clusters:
                                                   R.A                   Dec.             Mag.        Size        Const.

Messier 35 (NGC 2168)         06h 08.9’         +24d 20’           5.1        28’        Gemini

Messier 35 makes a good low power view that also has another small open cluster, NGC 2158 to its southwest.  In order to find it, let us go back to our old friend, Orion, that is west of straight South from my back yard at 36 degrees North in the early evening.  If you imagine a line running from the eastern star in Orion's belt, Zeta or Alnitak, through Orion's eastern shoulder star, Alpha or Betelgeuse, and on about one and a half times the Zeta to Alpha distance, you will see a second magnitude star called Mu Gemini.  This star is part of the “foot” of the northern twin.  Just to the west of Mu about a degree and a half or maybe a finger-width at arms length, is the variable star Eta (symbol looks like a fancy “n.” Just east and a little North of Eta is 1 Gemini.  Both Eta and 1 are roughly fourth magnitude.

Messier 35 is roughly 1 ½ degrees NE of 1 Gemini.  This is maybe a finger-width and is about the same as a field-width in my NG-70 with a 25 degree eyepiece.  If you can put 1 Gemini in your field of view and then move NE, you should find M-35.  You will come to the little NG 2158 first.  It is fairly compact while M-35 is more spread out.

Collinder 89                        06h 18’        +23d 38’    5.7         35’       Gemini

Collinder 89 is very near to M-35, maybe three degrees to the east and a little South.  It is also NW of M Gemini about a finger-width or 1 ½ degrees.  This open cluster is a little bit dimmer than M-35 and a little more spread out.  You should be able to see it with your 25 mm eyepiece.  It should stretch across about one-third of your field of view.

Collinder 106                      06h 37.1’      +05d 57’        4.6            45’    Monoceros

The constellation Monoceros, the Unicorn, is located just east or Orion.  It looks as if the horn of this unicorn could poke Orion on his eastern shoulder.  This is the area where we want to go.  Look for a fourth magnitude star maybe three fingers east and a finger and a half South of Betelgeuse, Orion's eastern shoulder star.  This is Epsilon Monoceros.  We have three of our objects in the neighborhood east of this star. Maybe a couple degrees or a fat finger-width east of Epsilon is the Rosette Nebula which we will talk about below.  Collinder 106 is about three degrees NE or Epsilon.  It is pretty big and will cover nearly half the width of your field with a 25mm eyepiece in an NG-70.  There is another smaller cluster to the southwest of 106 that may at least be partially in your field of view if you push 106 over near the upper right edge if you are using a refractor with a diagonal. (I think)

Collinder 107                      06d 37.7’         +04d 44’         5.1            35’        Monoceros

Collinder 107 is directly South and a smidgen east of 106 almost two degrees.  Just move your scope South from 106 and you should see it.  107 is a bit dimmer and smaller than 106.

NGC 2264 (Christmas Tree)  06d 41.1'          +09d 53'          3.9            20'        Monoceros

I have not looked at this one yet.  The name sounded fun, so I included it.  With a magnitude of 3.9, it should be easy to see in a 25 mm eyepiece.  But, you may want a higher power to zoom in a little.  It has an emission nebula associated with it, so be on the lookout for some haze.  The nebula may be too dim to see with any real light pollution, but we can hope for the best.

To find it, go back to Epsilon Monocerotis.  It is the tip of the Unicorn's horn.  There is a line of three stars that are about 3 ½ degrees apart that make up the top side of the horn with Epsilon being on the SW end.  The middle star is 13 and it is about as bright as Epsilon or just a touch dimmer. The next one just has the number 15 and is much dimmer.  The whole area around 15 is nebular material.  From what I can tell 15 is part of the Christmas Tree Cluster.

Just to the immediate South of this cluster is the Cone Nebula.  I don't know if we can make it out or not.  But, survey all around this cluster.  There are all kinds of objects shown in the Pocket Sky Atlas in this area.  Not much telling what you can see in the area.

Messier 50 (NGC 2323)        07d 03.2'          -08d 20'            5.9          16'        Monoceros

This is the last open cluster on our list in Monoceros.  It is farther South than the others and we need to approach it from another direction.  Let us go back to Orion and look to the eastern knee or foot, depending on your perspective.  This is Kappa Orionis or Saiph.  The bright star Beta Orionis or Rigel is in the same position on the west side.  From Saiph, go one and a half fists east to Sirius, or Alpha Canis Majoris.  This is the brightest star we see and should be hard to miss.

I normally think of Sirius as the big dog's eye, but most drawings show it as his shoulder with the head located NE.  From Sirius we want to look for a star to more North than east about five degrees or maybe half a fist.  This star is just barely visible to me from my yard.  This star is Theta Canis Major and is the dog's nose in drawings.  We want to imagine a line going from Sirius, skimming just to the South of Theta and on about that much farther.  At this spot, we should be on top of M-50.  With a width of 16 arc-minutes, it will be visible in a 25mm eyepiece.  However, you may want to try a higher power once you find it.

Southeast of M-50 about three degrees are two other small open clusters, NGC 2335 and 2343.  They are both on the Northern end of a large nebular area.  I think it is called IC 2177.  I do not know if we can see any of it, but it is there none the less. 

Messier 41 (NGC 2287)        06d 47.0'          -20d 44'            4.5          38'        Canis Major

South of Sirius about four degrees or two fat fingers, then a touch east, is M-41.  It is relatively bright and will cover about one-fourth the field-width of a 25mm eyepiece in an NG-70.

Another four degrees southeast of M-42 is the star O2 that is shown as one of the stars making up the figure of Canis Major.  This star is part of an open cluster called Collinder 121 that has several bright stars in it and is probably worth a look also.

Messier 47 (NGC 2422)        07d 36.6'          -14d 30'            4.4            29'        Puppis

About a fist width east and a finger North of Sirius is M-47.  There are several individual stars in this cluster are bright enough to show up on the Pocket Sky Atlas.

Messier 46  (NGC 2437)        07d 41.8'          -14d 49'            6.1            27'        Puppis

Look about a degree and a half east and a little South of M-47 to find M-46.  It is slightly smaller than M-47 and dimmer.  My star charts show a planetary nebula, NGC-2438, at the same location.  It is toward the North side of the cluster.  It is a little more than an arc-minute wide and magnitude 11.  I doubt that we can see it, but we can look.  Even if we cannot see it, we can feel a little smug knowing that it is there.

Messier 93  (NGC 2447)        07d 44.6'          -23d 52'            6.2            22'        Puppis

Since this cluster is east of Kappa Puppis, which is one of the double stars next month, I am changing my mind and will pull this one and put it in next month's list.

Nebula:

Rosette Nebula (NGC 2237)  06d 32.2'          +05d 03'                        80' x 60'    Monoceros

Remember Epsilon Monoceros?  The Rosette Nebula is straight east of that star maybe two finger-widths.  It is supposed to be visible in 50mm binoculars with a fairly dark sky.  Hopefully, we can see it with our telescopes.  There is a small open cluster, NGC 2244 in the middle of it.  There is another small cluster Collinder 97 about two degrees North of 2244.  97 is not in the Rosette.

Well, that is the end of the list for March.  I hope you have fun with it!

Thanks for reading!

Bill Steen




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